Data is stored in variables, which require memory space depending on the sort of value we assign to them. It’s easy to create variables in Python; just write the variable name on the left side of the equal sign (=) and the value on the right, as seen below. Python infers the type of the variable based on the value we are assigning, thus you are not required to state it directly.
num = 100 #num is of type int str = "Chaitanya" #str is of type string
Name of the variable: Identifiers
Id is another name for the variable name. While naming variables in Python, there are a few guidelines that you must adhere to.
1. Either a letter or an underscore (_) must always come before the variable name. For instance, the names _str, str, num, and _num are all acceptable names for variables.
2. A number cannot be the first character in the variable’s name. For instance, the variable name 9num is not acceptable.
3. Only alphanumeric letters and underscores (A to Z, a to z, 0-9, or _) may be used in the variable name; special characters such as %, $, and # are not permitted.
4. Python’s case-sensitivity for variable names means that num and NUM are two separate variables.
Example of Python Variable
num = 100 str = "BeginnersBook" print(num) print(str)
Multiple Python assignments
In Python, many variables can be assigned in a single statement similar to this.
x = y = z = 99 print(x) print(y) print(z)
99 99 99
Another example of multiple assignment
a, b, c = 5, 6, 7 print(a) print(b) print(c)
Variable plus and concatenation operation
x = 10 y = 20 print(x + y) p = "Hello" q = "World" print(p + " " + q)
The following error will appear if you attempt to use the + operator with the variables x and p.
unsupported operand type(s) for +: 'int' and 'str'
A data type identifies the kind of data; for instance, “hello” is a string kind of data while “123” is an integer. Python divides its data types into two groups:
1. Immutable data types: It is impossible to modify a value.
2. Types of data that can change their values
Python’s immutable data types include:
Python’s mutable data types include: